RJ45 specified the entire interface (ie which wires did what), not just the connector.

The “what” was of course not Ethernet.

A lot of connector series are are multi-sourced because big clients tend to require this. For example the 38999 series connectors used in military and aviation applications are made be TE, Amphenol, Souriau, ITT Cannon, Eaton...

So it's really not uncommon to have manufacturers make something thing that a different company is known for. I think it's basically just luck that Molex got the credit for it

Which “Molex connector” are you referring to? The ATX spec specifically specifies Molex Mini-Fit part numbers, and claims this is for compatibility with PCIe: https://cdn.instructables.com/ORIG/FS8/5ILB/GU59Z1AT/FS85ILB...

Is Mate-n-Lok perhaps a compatible product from a competitor?

...and Berg (0.1") connectors are now Dupont, even though Dupont doesn't make them anymore, and has had nothing to do with them since 1993. Everyone called them "Berg" in 1978 when I was first exposed to them, even though Dupont had acquired the product line from Berg in 1972.

https://www.reddit.com/r/electronics/comments/ioc6sf/i_final...

The combination of "When documenting" and referencing "J3" indicates that dlcarrier is referencing a limitation of a specific port on a product that they worked on, not a set of global limitations on any 8P8C connectors

I had assumed that the wires in the jack would rest along the bottoms of the blades in the plug, but I guess if it was never designed for high current applications, the contact area wouldn't be a consideration.

It took a few tries to get it right, but it's amazing that PoE is even an option given how far it is outside of the scope of what the cables and connectors were designed for. I've heard of locations that use it for power, instead of 120 V outlets, because it's cheaper and safer and most portable high-current appliances use batteries, while fixed high-current appliances use 240 V outlets.

Hot plugging is always a challenge, especially with direct current, and negotiation prevents that from being a problem while making a connection, but I never considered that unplugging isn't negotiated first. I wonder if IEC has ever considered using a locking latch, like an EV charger.

I have a PoE camera that I sometimes unplug to restart it, when it freezes up and I can't restart it from the web interface. I'll be sure to turn that port off first, before unplugging it.

You'll also enjoy annex H of https://usb.org/sites/default/files/USB%20Type-C%202.4%20Rel...

> While your preferred specification is excellent, It’s “an ethernet port” in ordinary usage. Or “ethernet jack” in more technical contexts and entirely sufficient for Ali Express.

Right, in your average 2020s home or office, "Ethernet" is almost certainly 8P8C (commonly known as RJ-45). In decades past it was more ambiguous – in the 1990s, coax – ThinNet/10Base2 – was still reasonably common; even the older ThickNet/10Base5 would still occasionally be encountered. So to some extent, being specific is a bit of an "old timer" trait–a habit picked up decades ago when it was still important, now maintained when it is rarely still necessary.

But even in the 2020s – in a factory, it could easily be M12 instead. Or even a mix of both – 8P8C in the offices, but M12 on the factory floor.

Honestly, even in a home environment, I hate how fragile and easily unplugged 8P8C connectors are (the worst part is when they get slightly pulled out, so they still look like they are plugged in, but the connection is dead or flaky). I've thought about using M12 at home before, but it probably wouldn't be very practical.

That does you no good in my line of work, where it's just as likely to be a serial port.

RJ45S and RJ45M are ordering codes for so-called “registered jack” configurations for terminal connections to the U.S. telephone network. These codes were defined until 2000 in the FCC Rules (47 CFR § 68.502(e)) and later in the TIA/EIA-IS-968 standard, and they refer to single and multiple arrangements of two wires and a programming resistor on a miniature eight-position keyed jack.

https://www.govinfo.gov/content/pkg/CFR-2000-title47-vol3/pd...

Unfortunately, the “RJ45” part of these codes has become a metonym for the unkeyed version of the miniature eight-position jack and plug, now widely used for Ethernet and other purposes, but strictly speaking, RJ45 refers to a different connector with totally incompatible wiring.

Specifically, what is colloquially an "RJ45" or "Ethernet" connector is an 8P8C "Bell System Miniature Plug/Jack" (AT&T's original name; it is a smaller version of the older Bell System connectors) / "miniature plug/jack" (FCC genericization of the name by removing "Bell System", even though the word "miniature" is no longer meaningful without context) / "modular jack" (ANSI/IEC genericization). That is what is meant when just "8P8C" is said.

Pedantically speaking, RJ45 (as first defined by AT&T internally[1], and later by the FCC's 47 CFR part 68) is not that. The RJ45 socket is a keyed 8P8C modular jack, not a regular 8P8C modular jack. Here is a photo: https://commons.wikimedia.org/wiki/File:RJ45_female_connecto...

[1]: The "RJ45" designation was originally an AT&T "USOC" (Universal Service Order Code). In the '70s, the FCC told AT&T that they had to allow interoperability from other companies, so the FCC had to publish a bunch of specifications; the meaning of "RJ45" became publicly specified in Bell System Communications' Technical Reference PUB 47101 "Standard Plugs And Jacks" (1979, though I think there might be an older number/revision from the early '70s that I haven't been able to track down). That (in combination with a few other technical references, such as PUB 47102), later became part of the Code of Federal Regulations, as 47 CFR part 68.

RJ45 is a specific AT&T USOC order code to slap a normal 8P8C jack on someone's wall to provide something like multi-line analog telephone service.

Well you definitely SHOULD say RJ45. We do a lot of networking at my job and if I asked for an 8P8C connector, I would get confused stares. Say Ethernet cable, Cat 6 cable (or whatever cat), or RJ45. Sometimes being correct isn’t the right thing to do.